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INDEX 



PAGE 

ngandae, Trentepohlia . . 320 
ugandaensis, Plecia iig, 120 (fig.), 

121 

uncinata, Plecia 120 (fig.), 121-122, 

124 (fig.) 

undulata, Psychoda . 47-48 (fig.) 
uniaculeata, Limonia . 235 (fig ), 

242-243 

unicornuta, Gonomyia 331 (fig.), 

333-334 

uniflava, Limonia . . 243 

unijuga, Limnophila . . PI. 28 
Uranotaenia . . . 30, 33 



vansomereni , Limnophila 287 (fig. ) , 

288-290 

vanstraeleni, Ormosia 341 (fig.), 346 
variegata, Styringomyia . . 379 



PAGE 

variitibia, Molophilus 361 (fig.), 363 
varipes, Pseudolimnophila . 279 
venusticeps, Nephrotoma 162, 
163 (fig.), 164-165 
venustipes, Hovamyia . . 335 
vicaria, Philia . 124 (fig ), 127 
victoria, Tipula . . 179 (fig.) 
vigilans, Molophilus 361 (fig.), 364 
vilhelmi, Limonia . . 243 

witteana, Teucholabis . . 321 
woosnami, Limonia 243, 244 (fig.) 



xenophallus Stryringomyia 

378 (fig.), 380 



zambeziensis, Tipula 



179 (fig-! 



BRITISH MUSEUM (NATURAL HISTORY) 



RUWENZORI EXPEDITION 

1934-5 



VOL. I. No. 1. 



INTRODUCTION 

WITH LIST OF LOCALITIES 



LONDON 

PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM 



ed 2Sth February 1939] 



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RUWENZORI EXPEDITION, 1934-5 



Reports upon the ENTOMOLOGICAL COLLECTIONS made by this 
Expedition will be issued in three volumes, as follows: 

Vol. I. Diptera Nematocera. 

Vol. II. Diptera Brachycera and Cyclorrhaplia. 

Vol. III. Other Insecta. 

It is not expected that the whole of the entomological collections will be 
reported upon, but on the other hand it is anticipated that it may in some 
instances prove convenient to include here information upon insect material 
obtained by other recent British expeditions to East x\frican mountains. 

Parts will be issued as they become available, and the series will be closed 
when it appears that it cannot usefully be continued. 

The title " Ruwenzori Expedition, 1934-5" has been chosen for brevity 
because the bulk of the material is from that district. 

Title pages, indexes, etc., will be issued on the completion of each volume. 

BOTANICAL COLLECTIONS: 

Although no decision has been reached in respect of the botanical collections, 
it is possible that an account of these may form a fourth volume in this series. 

C. FORSTER-COOPER 

Director 

British Museum (Natural History) 
S. Kensington 
London, S.W.7 

8lh January igj') 



I, I 



JABROLD AND SONS, LTD., NORWICH AND LONDON 



1. INTRODUCTION 



(With Plates I-XX) 

From time to time suggestions had been mooted, by members of the Uganda 
Government Services and other persons interested, for a floral and faunal survey 
of some of the high mountains in British East African territories. These sug- 
gestions resulted in 1934 in the approval by the Trustees of the British Museum 
of a proposal for a botanical-entomological expedition to Eastern Ruwenzori, 
and the appointment of two members of the Museum staff — Dr. F. W. Edwards 
(entomologist) and Dr. G. Taylor (botanist) to act as leaders. The expedition 
was supported by grants from the Percy Sladen and Godman funds, the Uganda 
Government, and Mme. de Horrack Fournier. The leaders proceeded to East 
Africa in September 1934, returning in March 1935; they were joined in Africa 
by Messrs. D. R. Buxton (then on locust investigations), J. Ford (Oxford 
University), E. G. Gibbins (Uganda Medical Department), T. H. E. Jackson 
(Kitale, Kenj-a), J. F. Shillito (Nyakasura School, Fort Portal), and P. M. Synge 
(Cambridge University), who assisted in the work of the expedition for varying 
periods. 

The main object of the expedition being to study the flora and insect fauna 
of Eastern Ruwenzori, two small parties were formed to explore concurrently 
the little-known valleys of the Namwamba and the Nyamgasani, and visits 
were also made to other parts of the range. In order to obtain material for 
comparative purposes brief expeditions were also arranged to three other 
mountainous districts — the Birunga range in south-west Uganda; Mount 
Elgon, on the Kenya-Uganda border; and the Aberdare Range, north-east of 
Nairobi; also to two lowland forest areas, the Kalinzu Forest, near Lake 
Edward, and the Budongo Forest, near Masindi. 

A siunmarized itinerary is appended to this introduction giving all the locali- 
ties from which insect specimens were obtained during the course of the expe- 
dition, together with dates when the visits were made and the names of the 
collectors in each locality. The position of the localities is indicated in the 
accomj)anying maps. Illustrated accounts of the expedition have been pub- 
lished in Natural History Magazine, Nos. 36-40 (1935-6), and in the book by 
P. M. Syngc, Mountains of the Moon (Lindsay Drummond, 1937). An account 
of the experiences of the party in the Nyamgasani Valley, by D. R. Buxton, 
will be found in Blackwood's Magazine for 1936. 

As regards the general results of the expedition, experience in tlio field and 

I, T 



2 



RUWENZORI EXPEDITION 



a preliminary survey of the collections suggests the following conclusions 
regarding the Ruwenzori insect fauna ; these conclusions may require modi- 
fications when the material has been more fully studied. 

1. The changes in the insect fauna noted in the ascent correspond with the 
vegetational and climatic zones. In the lower zones (up to 6000 feet altitude) 
the species are chiefly widespread lowland forms ; in the forest zones (6500-8000 
feet) is found the greatest variety of species, and most groups are well repre- 
sented; in the bamboo and lower heath zones (8000 to 11,000 feet) there is 
already very much less variety; finally in the upper heath and alpine zones 
(11-14,000 feet), the fauna is extremely poor in species (there are, for example, 
only three butterflies and only one Tipuline crane-fly native to these zones, and 
no Neuroptera or Orthoptera were found) but those which occur are for the 
most part different from those of the lower zones. 

2. The evidence obtained tends to negative the suggestion that local 
endemism occurs in the different valleys, at least to any appreciable degree; 
the insect faunas of each altitudinal zone appear to be similar in different valleys. 

3. In the forest and bamboo zones the insect fauna of Ruwenzori shows a 
marked resemblance to that of the Birunga Mountains, and very much less to 
that of Mt. Elgon and the Aberdares ; this is pronounced in the case of the butter- 
flies and the mosquitoes, the two groups most studied. In the case of the 
butterflies, Mr. Jackson is of the opinion that there are no true endemics on 
Ruwenzori, but that all the forms v/hich have been regarded as confined to the 
Ruwenzori forests will be found to have a wide distribution in the area between 
Lake Albert and Lake Kivu where conditions are suitable. 

4. In various families of Diptera and Lepidoptera a strong " Palaearctic " 
element is present in the zones above 10,000 feet altitude. This is the more 
noteworthy on account of the general paucity of the fauna. 

5. As in the case of other high mountains, Ruwenzori provides numerous 
examples of species which are brachypterous either in the female sex, or in both 
sexes; examples of such species were found in the Geometridae and Tineidae 
among the Lepidoptera, and in the Tipulidae (several genera), Sciarinae, 
Empididae, Phoridae, Sepsidae and Copromyzidae among the Diptera. On 
Elgon this phenomenon is even more noticeable, but in both localities it is 
probable that many of the cases of brach\'pterism are due to causes unconnected 
with elevation. Apart from brachypterism, no obvious cases of adaptation to 
mountain conditions were noted, and nothing to correspond with the 
"gigantism" of some of the plants. 

The following notes on the four distinct mountainous areas visited by the 
expedition of 1934-5 may be of interest to those who are not already familiar 
with East African geography; 

Aberdare Mountains. — A range about 50 miles in length running almost 
due north and south, its southern end extending to within about 50 miles 



INTRODUCTION 



3 



in a direct line north-north-west of Nairobi. The range has two main peaks, 
one in the northern portion, now known as Settima (named on The Times atlas 
Donio Lereko), the other towards the southern end, now known by the Dutch 
name of Mt. Kinangop (named Donio Ngishei on The Times atlas). Both these 
peaks reach an altitude of 13,000 feet or more, the saddle between them forming 
a plateau at about 11,000 feet altitude; a lower plateau at about 7-8000 feet 
altitude is extensively farmed and often referred to as the Kinangop plateau. 
Roughly speaking the range forms the eastern flank of the Great Rift Valley 
in its course through the Kenya highlands, the western flank being the Mau 
Escarpment. Between the altitudes of 7000 and 9000 feet the range is very 
heavily forested, the forest providing cover for many large mammals, including 
numerous elephant and buffalo, besides the scarce bongo and giant forest hog. 
Two distinct zones may be recognized in the forest, a lower zone with large 
trees, dominated by the "pencil cedar," and an upper one of almost pure 
bamboo; above these zones the country is mainly open and grass-covered. 
Though even the summits fall short of the permanent snow-line, frost and falls 
of snow occur at times. The streams are few in number and all small. 

Mt. Elgon. — A mountain mass lying about one degree north of the equator, 
just north-east of Lake Victoria, its south-eastern half lying within the territory 
of Kenya Colony, and its north-western half in the Uganda Protectorate. It 
does not, like the other mountains visited, form a range of peaks, but is rather 
a single mountain — an enormous extinct volcano with a diameter of about 50 
miles, the crater at its summit having a diameter of 4 or 5 miles; various minor 
peaks on the rim of the crater attain altitudes of 14,000 feet or slightly more. 
A topographical description of the mountain has been given by E. Nilsson 
(Geografiska Annaler, 1931), who also discusses the extent to which it was 
former!}' glaciated. It would seem that during a period corresponding more or 
less with the ice-age of Europe large glaciers covered most of the top of Elgon, 
down to an altitude of about 12,000 feet, but certain areas (including the head 
of the Sosion Valley, visited by the expedition) remained always free from ice. 
At the present time there is no permanent ice or snow on Elgon, though falls 
of snow or hail are frequent in and around the crater, and may lie for some days 
or weeks. About thirty streams or brooks radiate from the crater-rim, one of 
which takes its origin in the crater itself and forms the source of the Swam 
River, flowing through a deep gorge on the north-east side of the mountain. 

The cru])tion wliich formed Elgon probably took place in the late Tertiary, 
but the vok^ano was certainly extinct in pre-glacial times. On the soutli-eastcrn 
side of the mountain, visited by the expedition, cultivation extends to an alti- 
tude of nearly 7000 feet, above which (7000 to 8500 feet) is a forest zone with 
large open grassy glades. Above tlic forest there is very little bamboo, and 
upper forests of tree-heather have been largely destroyed b}- t ho Masai inliabi- 
taiits and their cattle, .■\bo\-c 10,000 feet altitude the count i\- i< iiuiio open 



4 



RUWENZORI EXPEDITION 



with only low bushes and scattered trees of Senecio; the herbage includes a 
large variety of shrubby Compositae, notably various species of Helichrysum. 

BiRUNGA (or Virunga) Mts. — A row of three volcanic cones in the extreme 
south-west corner of Uganda, just north-east of Lake Kivu, their summits on 
the boundary-line between Uganda and the Belgian Congo, adjoining the 
Belgian National Park (Pare National Albert) ; they form part of the Mufum- 
biro group which is mainly in Belgian territory and includes the larger volcanoes 
Karissimbi, Mikeno and Nyamlagira. These mountains are famous as being 
the headquarters of the eastern gorilla, which inhabits the extensive bamboo 
forests. The three peaks of the Birungas rise abruptly from the volcanic floor 
of the western rift-valley, which here lies at an altitude of about 6000 feet above 
sea-level; they are, from east to west, Muhavura (13,547 feet), Mgahinga (11,400 
feet), and Sabinio (11,960 feet), the three peaks being only about three or four 
miles apart. Even Muhavura does not reach the snow-line, and shows no 
evidence of former glaciation. Largely owing to the porous nature of the ground 
there are hardly any permanent streams. The mountains of this group were 
formed in the latest period of volcanic activity in East Africa, probably very 
late in the Tertiary ; some of those in the Congo still possess active craters. They 
have blocked the floor of the rift-valley, so that Lake Kivu, which formerly 
had an outflow to Lake Albert and so to the Nile, now discharges to the south. 

The rich volcanic soil of the rift-valley at the foot of the mountains is very 
highly cultivated and the district carries a large population. There is very 
little true forest on the mountains, but dense bamboo covers the zone between 
8000 and 9000 feet altitude; above this are found the zones of tree-heaths, 
Hypericum and Senecio, which extend to the summits; the plants in these 
zones do not attain such large dimensions as on Ruwenzori. 

RuwENZORi. — -A large block-mountain situated almost on the equator in 
the western rift-valley between Lakes Edward and Albert. It is the third 
highest mountain range in Africa, several of its peaks attaining an altitude of 
over 16,000 feet, and a large central area of the massif being above the present 
permanent snow-line. The glaciated area was formerly more extensive, though 
recent surveys have shown that the glaciers were not so widespread as at one 
time believed, their lower limit having been about 12,000 feet. The range 
experiences a heavier rainfall than most other East African mountains, and the 
streams arising on its slopes are numerous and of a good size; the amount of 
rainfall, however, decreases greatly towards the southern end of the range, 
and the plain between it and Lake Edward is semi-arid. Ruwenzori is also 
unique among the high mountains of East Africa in being formed of ancient 
crystalline rocks instead of volcanic lavas, but geologically speaking it is not an 
old range, its uplift from the surrounding area of old rocks having probably 
taken place in connection with if not subsequently to the formation of the rift- 
valley system about the middle of the Tertiary era. 



INTRODUCTION 



5 



A full description of Ruwenzori is given in the volumes describing the famous 
pioneer expedition of the Duke of the Abruzzi in 1906, and in the accounts of 
recent surveys made by air and on foot by Dr. Noel Humphreys in the years 
1925-6 and 1931-2 (see Geographical Journal, 69:516-531, and 82:481-514). 

The vegetation-zones on Ruwenzori are similar to those on other East 
African mountains, though with some differences. The area of long grass and 
cultivation gives place at about 6500 feet altitude to the mountain-forest, with 
a great variety of large trees and dense undergrowth especially of ferns and 
mosses; in the lower parts of the forest there are also extensive open areas 
clothed with bracken. The proportionate extent of the forest-zone and the 
succeeding bamboo-zone varies in different parts of the range ; in the Mobuku 
and Namwamba Valleys the forest-zone is extensive and the bamboo-zone but 
little developed, whereas the reverse is the case in the Nyamgasani Valley. 

The scenery of the mountain areas visited by the Expedition is illustrated 
in the accompanying Plates I-XX as follows: 

Aberdare Mountains: Plate L 
BiRUNGA Mountains: Plates II-III. 
Ruwenzori: 

Namwamba Valley: Plates IV-VIH. 

Nyamgasani Valley: Plates IX-XIIL 

Mobuku Valley : Plate XIV. 

Northern Spur: Plates XV-XVl. 
Mt. Elgon (Kenya side): Plates XVII-XX. 

Further illustrations, depicting specific habitats, accompany the various 
reports of specialists. 

The present volume comprises reports upon the Diptera Nematocera 
collected by the Expedition; Volume II deals with the Diptera Brachycera 
(inckiding Cyclorrhapha); and Volume III with insects of various orders other 
than Diptera. 



LIST OF LOCALITIES 



{With dates, names of insect collectors, and maps) 



I. Nairobi and the Aberdare Mts. {F. W. Edwards and /. Ford): 



Katamaj^o River, Kikuyu Escarpment 
Ruiri Falls 

Ngong Hills, W. of Nairobi 
Thika and Chania Falls, N.-E. of Nairobi 
Mt. Kinangop, Aberdares 

On journey to Kigezi (F. W. Edwards and E. G. 
Kampala, Uganda 
Entebbe . . 

Kalungi Swamp, W. of Entebbe 
Masaka and Lake Nabugabo . . 
Mbarara and Ruizi Falls 

Kigezi District, S.-W. Uganda [F. W . Edwards, J 
Mabungo Camp, c. 6000 feet . . 
Mt. Muhavura, camp at 11,000 feet . . 
Mt. Mgahinga, summit, c. gooo feet . . 
Mt. Sabinio, Lugezi Camp, 7-8000 feet 
Mt. Sabinio, summit, 10-11,000 feet . . 
Lake Mutanda (/. Ford) 
Kanaba Gap and Muko, Kigezi Mts., c. 7500 
feet 



Ruwenzori and neighbourhood. 



21.X.34. 

21. X.34. 

22. x. 34. 

23- X-34- 
25.x.-2.xi.34. 

ibbiiis): 
6-11.xi.34. 
9.xi.34 and 13.xii.34. 

12. xi.34. 

13. xi.34. 
14-15.xi.34. 

Ford and E. G. Gihhins) 

16- 30. xi. 34. 

17- 18.xi.34. 
22.xi.34. 
20-28. xi. 34. 

24- 25.xi.34. 

18. xi.34. 

19. xi.34. 



(«) Namwamba Valley (F. W. Edwards and T. H. E. Jackson) : 

Kilembe, 4500 feet, grass zone 1-3 and 15-28. xii. 34, 21-22.1.35 

Kyanjoke Camp, 6500 feet, forest zone .. 2-4 and 13-19.1.35. 

Kararama Camp, 8300 feet, bamboo zone . . 5-1. 35- 

Kiriruma Camp, 10,200 feet, lower heath zone 6-7 and io.i.35. 

Kaihinguru Camp, 11,500 feet [E. G. Gihbins) 20. xii. 34. 

Kasinjiko Camp, 12,500 feet, upper heath zone 8.1.35. 

Kitandara Camp, 13,200 feet, alpine zone . . 24. xii. 34 [E. G. G.) 

9.1.35 [F. W. E.) 



RUWENZORI EXPEDITION 



5 (0 ISMiJes 




Map 2. — Ruwenzori Range. 
Showing localities visited by expedition. 



LIST OF LOCALITII'S 



9 



Nyamgasani V;ille\' (I). R. Iruxloii): 
Bwito, 5000 feet, grass zone . . 
Camp I, 6000 feet, forest zone 
Camp II, 7500 feet, bamboo zone 
Camp III, 9000 feet, lower lieatli zone 
Camp IV, 12,000 feet, upper licatli zone 
Camp V, 13,000 feet, npi)er lieatii zone 
Camp VI, 12,800 feet, by seventh lake 
Camji VII, 13,500 feet, alpine zone by fourth 



20.xu.34. 
21-26. -xii. 34. 
27-3i..\ii.34. 
1-8.1.35. 
9-12.1.35. 

i3-i5-i-35- 
16-23.1.35. 

24-26.1.35. 



(0 



(ci) 



Mobukn* Valley (/''. \V. Edwards and /. F. Sltilliln): 
North bank, 4000 feet . . . . . . . . 3.XII.34. 

Rikoni, 7-8000 feet . . . . . . . . 29-31. xll. 34. 

Il)an(la, 5000 feet .. .. .. .. 20.1.35. 

Nortliern sj)ur and P'ort Portal district (F. W. Edwards and /. F. Shillito) 
Buhundo, Bwamba Pass (West Side), 7500 feet 28-31.1.35. 



(/) 



Mt. Karangora, 9900 feet . . . . 
Nyakasura, S.-W. of Fort Portal 
Fort Portal (Toro) 

Mpanga (Kibale) Forest, E. of Fort Portal 
Katwe Salt Lakes (/'". W . Edi&ards) 
Kalinzu I-'orest {'I'. H . E. JacksO)i) 



I.U.35- 

3. xll. 34 and 23-24.1.35. 

4. xli.34. 

15. xii. 34 and 25.1.35. 
I and 26. xii. 35. 

25-i-i935- 



Masindi district. Lake Albert (/•". IT. Juiwards): 

Budongo Forest . . . . . . . . 5-^>.il.35. 

Wakl FalU 8.11.35. 

Murcliison I'alls (no insects) . . . . . . g-10.li.35. 



Mt. I'.li^on (Uganda side) (/. Ford) 



VU1.1934. 



Mt. i'dgon, S.E. (Kenya side) (/•'. II'. Edwards and /'. //. E. Jackson): 

Kaprctwa, 6000 feet . . . . 15-i1S.ii.35 and 4.111.35. 

Swam Kiver, 4000 feet .. .. .. .. 18.ii.35. 

I'orest zone, 8000 feet . . . . . . . . i9.ii.35. 

lli alli and alpine zones, 10-14,000 feet . . 20.ii.-2.iii.35. 



Nakuru DiNtricl (/■. I!'. I'dxi'ards): 
Lake Nakuru 

Hills N.-K. of Nakuru, 9000 feet 
ThoiVison's I'^alls, 7000 feet 

* This nainc slicmld !.<■ spelt MntniUu dr^t,- ]. T. Slnllit.-V 

I. ih 



5-iii-35- 
6.iii.35. 
6.iii.35. 



A OF 



Plate I 
Aberdark Mountains 
Summit of Mt. Kinangop 



Plate II 
BiRUNGA Mountains 
Muhavura, Mgahinga and Sabinio 
(View across rift-\'alley from Kanaba) 



Plate 111 
BiRUNGA Mountains 
Sabinio from Lugezi Camp 



Plate IV 

RuwENZORi: Namwamba Valley 
Kilembe (Expedition Head-quarters) 



DGPARTMENT ' 



Plate V 

RuwENZORi: Namwamba Valley 
View from Kasinjiko Camp : Sunrise 
(Arrow points to Okuleba Summit) 



RUWKNZORI EXPEDITION — VOL. I 



PLATE V 




Plate VI 

RuwENZORi: Namwamba Valley 
Kitandara Camp, 13,000 feet 



KUWENZORI i:X I'K DITION — VOL. I 



PLATE VI 




Plate VII 
RuwENZORi : Namwamba Valley 
View south-east from Kitandara Camp 



RUWENZORI i'XPl'DITION \'()r, . I 



I'l ATI' \ I 




. DEPARTMENT 




Plate VIII 

RUWENZORI 

View from Summit of Okuleba 
(The snow peaks to left and in centre are parts of Mt. Baker) 



RUWENZORl !•. X I'l' DITION — VOL. I 




PI a I ''x ; 

RUWENZORI: NYAJ.u.vi l/. AT.LEY 

Camp on Ridge at - feet. 
(P. M. Synge (Botanist) and P. S. Somei .■ .;e (Artist) by tent) 



Plate X 

RuwENZoRi: Nyamgasani Valley 
Eighth (Lowest) Lake 



Plate XI 

RuwENZORi: Nyamgasani Valley 
Above: Upper part of Gorge with Seventh ar.d Eighth Lakes 
Below: Seventh Lake 



Plate XII 
RuwENZoRi: Nyamgasani Valley 
Sixth Lake 



Plate XIII 

ROWENZORI 

View from Weissman Peak 
(Lejl: Mt. Stanley; Centre: Mt. Speke; Right: Mt. Baker) 



Plate XIV 
RuwENZoRi: MoBUKU Valley 
Portal Peaks (in cloud) from Bikoni Hill 



RUWENZORI EXPEDITION 



— VOL. I 



PLATE XIV 




Plate XV 
Ruwenzort: Northern Spur 
Tree-Ferns on the Bwamba Pass 



RUWENZOKI EXIM'DITION — VOL. I 



PLATK XV 




Plate XVI 
RuwENZORi: Northern Spur 
Nyakasura Crater-lake 



R II WIC N ZOR I F.XIMC DITION- VOL. I PLATI', XVI 




Plate XVII 

Mt. Elgon from near Endebess (20 miles eastwards) 
(The dip in centre of sky-line marks position of Swam Gorge) 



RUWICNZOKI KX IM'. DIT ION -vol.. I 



Plate XVII I 
Mt. Elgon 
Koitobboss Summit 



RUWENZORI EXPEDITION — VOL. I 



PLATE XVIII 




Plate XIX 
Mt. Elgon 
Head of Sosion Valley with Peak 14170 
(indicated by arrow) 




DEPARTMENT 



Plate XX 
Mt. Elgon 
View from Peak 141 70, showing Tarn 



I-